Pyronyl-pyrylium sensitizers for electrophotographic organic photoconductors

ABSTRACT

Novel sensitizers for use in electrophotographic organic photoconductors, which are compounds having the following general formula:   (WHEREIN EACH OF R1 and R2 represents a radical selected from the group consisting of hydrogen, alkyl having 1 - 2 carbon atoms, alkoxy having 1 - 2 carbon atoms, halogen and nitro, each of n1 and n2 represents an integer from 1 to 2 in the case where said R1 and R2 represent a radical other than hydrogen, each X and Y when present, represent a fused phenyl nucleus having at most two substituents selected from the group defined for said R1 and R2 and Z represents an anionic functional group).

United States Patent 11 1 Kubota 1 Sept. 23, 1975 [75] Inventor:

[73] Assignee: Kabushiki Kaisha Ricoh, Tokyo,

Japan 22 Filed: on. 4, 1973 21 Appl. No.: 403,402

Tomio Kubota, Tokyo, Japan [30] Foreign Application Priority Data Oct.6, 1972 Japan 47-100799 Oct. 6, 1972 Japan 47-100800 Oct. 6, 1972 Japan47-10080] [52] US. Cl ..96/1.6; 260/3432 [58] Field of Search 96/16,139; 260/3432 [56] References Cited UNITED STATES PATENTS 2,378,5836/1945 Schmidt et a1. 260/3432 R X 3,526,502 1/1970 Murakami et a1.96/1.6 X 3,712,811 1/1973 Murakami et a1. 96/16 Primary ExaminerRolandE. Martin, Jr. Attorney, Agent, or Firm-Co0per, Dunham, Clark, Griffin &Moran 57 ABSTRACT Novel sensitizers for use in elcctrophotographicorganic photoconductors, which are compounds having the followinggeneral formula:

(wherein each of R and R represents a radical se lected from the groupconsisting of hydrogen, alkyl having 1 2 carbon atoms, alkoxy having 1 2carbon atoms, halogen and nitro, each of n, and n represents an integerfrom 1 to 2 in the case where said R and R represent a radical otherthan hydrogen, each X and Y when present, represent a fused phenylnucleus having at most two substituents selected from the group definedfor said R, and R and 2 represents an anionic functional group),

26 Claims, 19 Drawing Figures US Patent Sept. 23,1975 Sheet 1 of 43,97,561

FIG. I (SENSITIZER NO.

5 4o 50 Go 70 E WAVELENGTH (WXIO) 1. FIG. 2 (SENSITIZER NO. 2) I Q Go ToWAVELENGTH (m xlo) FIG. 3 (SENSITIZER No.3) I

a 40 50 Go E WAVELENGTH (W10) 5, FIG. 4 (SENSITIIZER No.4) I

5f WAVELENGTH (TmxIO) 6, FIG. S IGENGITIZ ER NO. 5 I

III

5E WAVELENGTH (mono) US Patsnt Sept. 23,1975 Sheet20f4 3,907,561

5 FIG. 6 (SENSITIZER NO. 6) 5 40 5'0 6'0 70 (1): O 5E N E WAVELENGTH('rmXIO) FIG. 7 (SENSITIZER NO.7) z 4'0 5'0 6'0 7'0 M- (j) 2 EWAVELENGTH (n'mXIO) '7 FIG. 8 (SENSITgZER NO. g3) 6O I a. WAVELENGTH(nWIO) l a FIG. 9 (SENSITIIZER No.9 I a. 40 50 o 70 8t 1-2 0|-WAVELENGTH (mnxlO) US Patent Sept. 23,1975 Sheet 3 of4 3,907,561

FIG. IO (SENSIT'IZER NO. 0) I g; 40 so 60 7o O 6| 5E WAVELENGTH (n'mXIO)FIG. II (SENSITIIZER NQIII) 9 4o 50 6O 70 5|- g WAVELENGTH (mnXIO) 6FIG. I2 (SENSITIZER NO. I2) I z 4'0 5'0 6'0 70 t 82 BI- 55WAVELENGTHMIXIO) FIG. I3 (SENSITIIZER NO. 3)

.TIVITY WAVELENGTH (mnxIO) FIG. I4 (SENSITIZER NO. I4

TIVITY PHOTOSENSI- PHOTOSENSI- WAVELENGTH (n'mXIO) US Patant Spt.23,1975 Sheet4 f4 3,907,561

FIG. [5 (SENSITJZER NO. I)

WAVELENGTH (WXIO) FIG. |6(SENS|TIZER NO. I6)

WAVELENGTH (1m XIO) FIG. |7 $EN$|T|ZER NO. I7)

WAVELENGTH (mnxlO) FIG. |8(sENs|TqzER No.15)

WAVELENGTH (n'mXIO) FIG. I9 (SENSITIIZER NO. l9

WAVELENGTH (mnxlO) PYRONYL-PYRYLIUM SENSITIZERS FOR ELECTROPHOTOGRAPHICORGANIC PHOTOCONDUCTORS BACKGROUND OF THE INVENTION a. Field of theInvention The present invention relates to scnsitizer s for use inelectrophotographic organic photoconductors. which act to increase thechemical sensitivity and the optical or spectral sensitivity of organicphotoconductors for use in electrophotography.

b. Description of the Prior Art The sensitizers of the present inventionare novel compounds. Application of such compounds to clectrophotography is therefore unprecedented.

SUMMARY OF THE INVENTION The object of the present invention is toprovide novel sensitizers for use in electrophotographic organicphotoconductors, said sensitizers are compounds expressed by thefollowing general formula:

(wherein each of R and R represents a radical selected from the groupconsisting of hydrogen, alkyl having 1 2 carbon atoms, alkoxy having I 2carbon atoms, halogen and nitro, each of n and 11 represents an integerfrom I to 2 in the case where said R and R represent one radical otherthan hydrogen, each of X and Y when present, represent a fused phenylnucleus having at most two substituents selected from the group definedfor said R and R and Z represents anionic functional group).

Compounds within the scope of this general formula can be divided intocompounds having the general for mulas (I), (II), (III) and (IV) asfollows:

Compounds of the the general formula (II) wherein each of R and Rrepresents hydrogen, an

alkyl group having I or 2 carbon atoms, an alkoxy group having I or 2carbon atoms, halogen or nitro group; each of i1, and n represents aninteger from 1 to 2 in the case where said R and R representa radicalother than hydrogen.

Compounds of the general formula (II) wherein R R Z", n and narerespectively the same as defined in the general formula (I).

Compounds of the general formula (III) wherein R R Z, n, and n arerespectively the same as defined in the general formula (I).

Compounds of the general formula (IV) wherein R R Z, n, and n arerespectively the same as defined in the general formula (I).

All the compounds expressed by the foregoing general formulas (I) to(IV) are yellow or pink crystalline dyestuffs showing the maximumabsorption wavelength (A max) of 450 660 nm. They are readilysynthesized by reacting an acetyl coumarin derivative derived fromsubstituted Z-hydroxybenzaldehyde with substituted 2-hydroxybenzaldehydein the presence of a mineral acid.

The following are typical examples of the synthesis of the compounds ofgeneral formula (I).

a. Synthesis of sensitizer No. l: 2-[3-(l,2)-benzopyronyl]-benzopyrylium perchlorate (wherein R and R hydrogen.Z: ClOf, n and n 1) After dissolving 4.2 g of 3-acetyl coumarin and 3 gof 2-hydroxybenzaldehyde in ml of dehydrated ethyl ether and adding 12ml of 7071 pcrchloric acid, hydrochloric acid gas was introduced intothe mixture to saturate it at a temperature of 0 30C. After leaving thethus reacted solution standing overnight in an icebox and thensubjecting it to suction filtration, the resulting crude crystals werethoroughly washed in water and rinsed with ethyl ether. Subsequently,the thus treated crude crystals were recrystallized from 200 300 ml ofnitrobenzene. whereby 6 g of the objective compound in theform ofcrystalhaving ainelting point of 286. 1 C. were obtained. This compound wasbrown in color. Its nitromcthane solution showed a maximum absorptionwave-length of450 nm and the extinction coefficient (e/10) of itsmolecule was 1.17.

b. Synthesis of sensitizer No. 2: 6-methoxy-2-l 6-methoxy-3-(1.2)-benzopyronyll-ben'zopyrylium perchlorate (wherein R, andR methoxy group. 7.: C10 n, and n 1) By dissolving 4.6 g of3-acetyl-6-methoxy coumarin and 3 g of 2-hydroxy-5-methoxybenzaldehydein 150 ml of dichloroethane and applying the same procedure as that forthe synthesis of sensitizer No. 1. 9 g of the objective compound in theform of crystals having a melting point of 262C. were obtained. Thiscompound is brown in color. Its nitromcthane solution showed a maximumabsorption wave-length of 505 nm and the extinction coefficient (e/10)of its molecule was 1.21.

c. Synthesis ofsensitizer No. 3: 6-chloro-2-[6-ehloro- 3-( 1.2)-benzopyronyll-benzopyrylium perchlorate (wherein R and R chlorogroup, Z: C10 n and n 1 By dissolving 4.6 g of 3-acety1-6-chlorocoumarinand 3 g of 2-hydroxy-5-chlorobenza1dehyde in 200 ml of dichloroethaneand applying the same procedure as for the synthesis of the sensitizerNo. 1, 3 g of the objective compound in the form of crystals having amelting point of 272 274C were obtained. This compound was brown incolor. Its nitromcthane solution showed a maximum absorption wave-lengthof 460 nm and the extinction coefficient (e/lO") of its molecule was0.38.

d. Synthesis of sensitizer No. 4: 6-nitro-2-[6-nitro-3- 1.2)-benzopyronyl l-benzopyrylium perchlorate (wherein R and R nitro group.Z: ClO n and n By dissolving 4.7 g of 3-acetyl-6-nitrocoumarin and 3.3 gof 2-hydroxy-5-nitrobenzaldehyde in 200 ml of dichloroethane andapplying the same procedure as for the synthesis of the sensitizer No.l, 2.5 g of the objective compound in the form of crystals having amelting point of 270 272C were obtained. This compound was brown incolor. Its nitromcthane solution showed a maximum absorption wavelengthof 502 nm and the extinction coefficient (e/10") of its molecule was1.06.

e. Synthesis of sensitizer No. 5: 6-bromo-2-[6- bromo-3-(1.2)-benzopyronyl]-benzopyrylium perchlorate (wherein R and R brofnogroup. Z. ClO n and n 1 By dissolving 4.5 g of 3-acetyl-6-bromocoumarinand 3.2 g of 2-hydroxy-S-bromobenzaldehyde in 200 ml of dichloroethaneand applying the same procedure as for the synthesis ofthe sensitizerNo. l. the objective compound in the form of crystals having a meltingpoint of 266 268C was obtained. This compound was brown in color. Itsnitromcthane solution showed a maxima absorption wave-length at 606 nmand 657 nm and the extinction coefficient (e/10") of its molecule was0.09 and 0.10. The following are typical examples of the synthesis ofthe compounds of general formula (11).

21. Synthesis of sensitizer N0.6:2-[3-(l,2,BB,anaphthopyronyl)]-benzopyry1ium perchlorate (wherein Rhydrogen, R2: hydrogen, Z C104, n.: 1, 2: 1)

After dissolving 4.8 g of 3-acetyl naphthocoumarin and 3.0 g of2-hydroxybenzaldehyde in 200 ml of diehloroethane and adding 12 ml of7071 perchloric acid hydrochloric acid gas was introduced into themixture to saturate it at a temperature of 0 C. After leav ing thethusreacted solution standing overnight in an icebox and then subjecting itto suction filtration. the resulting crude crystals were thoroughlywashed in water and rinsed with-fethyl ether. Subsequently. the thustreated crude crystals were recrystallized from 200 300 ml ofnitrobenzene. whereby the objective compound in the form of crystalshaving a melting point of 241 243C were obtained. This compound wasorange-colored. Its nitromcthane solution showed a maximum absorptionwave-length of 500 nm and the extinction coefficient (e/l0) of itsmolecule was 1.23.

b. Synthesis of sensitizer No. 7: 2-[3-{l.2.B.a-(7- nitr'onaphthopyronyl]-6-methoxybenzopyrylium perchlorate (wherein R nitro group. R methoxygroup, Z: C10 11,: 1. n- 1) By dissolving 5.0 g of3-acetyl-7-nitrocoumarin and 3.5 g of 2-hydroxy-6-methoxybenzaldehyde in200 ml of dichloroethane and applying the same procedure as for thesynthesis of the sensitizer No. 6 3.2 g of the objective compound in theform of crystals having a melting point of 168 170C were obtained. Thiscompound was ocher-colored. Its nitromcthane solution showed a maximumabsorption wavelength of 532 nm and the extinction coefficient (e/10) ofits molecule was 1.49.

c. Synthesis of sensitizer No. 8: 2-[3-{1.2.B,a-(7-chloronaphthopyronyl)} ]-6ehlorobenzopyrylium perchlorate (wherein Rchloro group. R chloro group. 7.. C10 n 1. n 1) By dissolving 5.0 g of3-acetyl-7- chloronaphthocoumarin and 3.5 g of 2-hydroxy-6-chlorobenzaldehyde in 200 ml of dichloroethane and applying the sameprocedure as for the synthesis of the sensitizer No. 6 2.3 g of theobjective compound in the form of crystals having the melting point of290 292C were obtained. This compound was brown in color. Itsnitromcthane solution showed maxima absorption wavelengths at 601 nm and649 nm and the extinction coefficient (e/10*) of its molecule was 1.14and 1.05.

d. Synthesis of sensitizer No. 9: 2-[3-(1.2.B,anaphthopyronyl)l-6-methoxybenzopyrylium perchlorate (wherein R hydrogen.R nitro group. Z. C10 n 1. n 1) 1 By dissolving 4.8 g of 3-acetylnaphthocoumarin and 3.5 g 2-hydroxy-6-methoxybenzaldehyde in 200 ml ofdichloroethane and applying the same procedure as for the synthesis ofthe sensitizer No. 6. the objective compound in the form of crystalshaving a melting point of 179 181C was obtained. This compound wasorange-colored. Its nitromcthane solution showed a maximum absorptionwave-length of 542 nm and the extinction coefficient (e/l0 of itsmolecule was 1.06. The following are typical examples of the synthesisof the compounds of general formula (III).

a. Synthesis of sensitizer No. 10: 2-[ 3-( 1.2benzopyronyll-B-naphthopyrylium perchlorate (wherein R hydrogen. Rhydrogen. 7.. C10 n, and n 1) After dissolving 2.1 g of 3-acetylcoumarin and 2.1 g of 2-hydro xy B-naphthoaldehyde in 200 ml ofdichloroethane and adding 12 ml of 7071 perchloric acid hydrochloricacidgas was introduced into the mixture to saturateit at'a temperatureof 0 30C. After leaving the thus reacted solution standing overnight inan icebox and then subjecting it to suction filtration. the resultingcrude crystals were thoroughly washed in water and rinsed with ethylether. Subsequently. the thus treated crude crystals were recrystallizedfrom 200 4 300 ml of nitrobenzene. whereby 0.2 g of the objectivecompound in the form of crystal having a melting point of 294 296C wereobtained. This compound was orange-colored. lts nitromethane solutionshowed a maximum absorption wave-length (A max) of 496 nm and theextinction coefficient (6/10") of its molecule was 2.94.

b. Synthesis of sensitizer No. 11: 2-{6-methoxy-3- 1.2 )-benzopvronyll-B-naphthopyrylium perchlorate (wherein R methoxy. R hydrogen. Z:C I1 and n 1) By dissolving 2.3 g of 3-acetyl-o-methoxycoumarin and 2.1g of 2-hydrt xy-fl-naphthoaldehyde in 200 ml of dichloroethane andapplying the same procedure as for the synthesis of the sensitizer No.10. 1.3 g of the objective compound in the form of crystals having amelting point of 285 287C were obtained. This compound was brown incolor. lts nitromethane solution showed a maximum absorption wavelength(A max) of 512 nm and the extinction coefficient (e/lO) of its moleculewas 2.02.

c. Synthesis of sensitizer No. 12: 2-[6-chloro-3( 1.2)-benzopyronyll-B-naphthopyrylium perchlorate (wherein R chloro group, Rhydrogen. Z: C10 1): and n l I By dissolving 1 g of3-acetyl-6-chlorocoumarin and l g of 2-hydroxy-B-naphthoaldehyde in200ml of dichloroethane and applying the same procedure as for thesynthesis of the sensitizer No. 10 thereafter. 1.7 g of the objectivecompound in the form of crystals having a melting point of 290 291C wereobtained. This compound was yellowish brown in color. lts nitromethanesolution showed a maximum absorption wavelength (A max) of 493 nm andthe extinction coefficient (E/lO") of its molecule was 2.56.

(1. Synthesis of sensitizer No. 13: 2[3-( 1.2)-benzopyronyl1-5,7-dinitro-B-naphthopyrylium perchlorate (wherein Rhydrogen. R nitro group, Z: C10 11,: 1. n 2) By dissolving 0.5 g of3-acetyl coumarin and 0.5 g of 2-hydroxy-6.8-dinitro-,8-naphthoaldehydein 200 ml of dichloroethane and applying the same procedure as for thesynthesis of the sensitizer No. 10.0.2 g of the objec' tive compound inthe form of crystals having a melting point of 278 280C were obtained.This compound was brown in color. Its nitromethane solution showed amaximum absorption wavelength (A max) of 514 nm and the extinctioncoefficient (6/10 of its molecule was 2.15.

e. Synthesis of sensitizer No. 14: 2-[6-bromo-3-( 1,2benzopyronyll-B-naphthopyrylium perchlorate (wherein R bromo group. Rhydrogen, Z: C10 1 I1 and n 1) By dissolving 2.3 g of3-acetyl-6-bromocoumarin and 2.1 g of 2-hydroxy-B-naphthoaldehyde in 200ml of dichloroethane and applying the same procedure as for thesynthesis ofthc sensitizer No. 10. 1.4 g of the objective compound inthe form of crystals having a melting point of 294 295C were obtained.This compound was light brown in color. lts nitromethane solution showeda maximum absorption wavelength (A max) of 493 nm and the extinctioncoefficient (6/10") of its molecule was 2.56. The following are typicalexamples of the synthesis of the compounds of general formula (IV).

a. Synthesis of sensitiyer No. 15: 2-| 3-( 1.213.0- naphthopyronyl)]-fi-naphthopyrylium perchlorate (wherein R and R hydrogen. Z (KL .11and n 1 1 After dissolving 4.2 g of 3-acetyl naphthocoumarin and 3 g ofZ-hydroxy-1-naphthtnildehyde in ml of dehydrated ethyl ether and furtheradding 12 ml of 70% perchloric acid. the resulting solution was satu'rated with hydrochloric acid gas at a temperature of 0 30C. The thustreated solution was left standing overnight in an icebox and thereaftersubjected to sue tion filtration. The residue was thoroughly washed inwater. rinsed with ethyl ether and recrystallized from 200 300 ml ofnitrobenzene. whereby 5.5 g ofthe objective compound in the form ofcrystal having a melting point of 248C were obtained. This compound waspink in color. lts nitromethane solution showed a maximum absorptionwave-length (A max) of 545 nm and the extinction coefficient (e/10) ofits molecule was 3.49.

b. Synthesis of sensitizer No. 16: 2-[3-{1.2.,B. a47-nitronaphthopyronyl ]-7-nitro-,8-naphthopyrylium perchlorate (wherein Rand R nitro group. 7. C10 n, and n 1) After dissolving 0.2 g of3-acetyl-7- nitronaphthocoumarin and 0.2 g of2-hydroxy-6-nitrol-naphthoaldehyde in 45 ml of dehydrated ethyl etherand adding 2 ml of 70% perchloric acid. the resulting solution wassaturated with hydrochloric acid gas at a temperature of 0 30C. The thustreated solution was left standing overnight in an icebox and thereaftersubjected to suction filtration. The residue was thoroughly washed inwater. rinsed with ethyl ether and recrystallized from 200 mlofnitrobenzene. whereby 0.17 g of the objective compound in the form ofcrystals having a melting point of 287 -289C were obtained. Thiscompound was orange in color. Its nitromethane solution showed a maximumabsorption wavelength (A max) of 530 nm and the extinction coefficient(6/10") of its molecule was 2.84.

c. Synthesis of sensitizer No. 17: 2-[3-{1.2.B,a-(7- nitronaphthopyronylLB-naphthopyrylium perchlorate (wherein R nitro group. R hydrogen. Z:C10 n and n 1 After dissolving 0.5 g of 3-acetyl 7 nitronaphthocoumarinand 0.5 g of 2-hydroxy-1- naphthoaldehyde in 45 ml of dehydrated ethylether and adding 2 ml of 70% perchloric acid. the resulting solution wassaturated with hydrochloric acid gas at a temperature of0 30C. The thustreated solution was left standing overnight in an icebox and thereaftersubjected to suction filtration. The residue was thoroughly washed inwater. rinsed with ethyl ether and recrystallized from 200 300 ml ofnitrobenzene. whereby 0.4 g of the objective compound in the form ofcrystals having a melting point of 262 264C were obtained. This compoundwas orange-colored. and its nitromethane solution showed a maximumabsorption wavelength (A max) of 534 nm and the extinction coefficient(6/10 of its molecule was 16.0.

d. Synthesis of sensitizer No. 18: 2-[3-{1.2.B,a-(9-chloronaphthopyronyl)} J-B-naphthopyrylium perchlorate (wherein R chlorogroup. R hydrogen, Z: C10- {in and n 1) After dissolving 0.5 g of3-acetyl-9- chloronaphthocoumarin and 0.5 g of2-hydroxy-lnaphthoaldehyde in 45 ml of dehydrated ethyl ether and adding6 ml of 70% perchloric acid, the resulting solution was saturated withhydrochloric acid gas at a temperature of 30C. The thus treated solutionwas left standing overnight in an icebox and thereafter subjected tosuction filtration. The residue was thoroughly washed in water. rinsedwith ethyl ether and recrystallized from 200 301) ml of nitrobenzene.whereby 0.6

g of the objective compound in the form of crystals having a meltingpoint of, 278 280C were obtained. This compound was orange-colored. ltsnitromethane solution showed a maximum absorption wavelength (X max) of554 nm and the extinction coefficient (6/10") of its molecule was 5.72.

0. Synthesis of sensitizer No. 19: 2-[3-( 1.2.8.01-naphthopyronyl)]9-chloro-62-naphthopyrylium perchlorate (wherein R,:hydrogen. R chloro group. 2 C10 n and 11 1]) After dissolving 0.5 g of3-acetyl naphthocoumarin and 0.5 g of2-hydroxy-4-chloro-l-naphthoaldehyde in 90 ml ofdehydrated' ethyl etherand adding 6 ml of 70% perchloric acid. the resulting solution wassaturated with hydrochloric acid gas at a temperature of 0 30C. The thustreated solution was left standing overnight in an icebox and thereaftersubjected to suction filtration. The residue was thoroughly washed inwater. rinsed with ethyl ether and recrystallized from 200 300 ml ofnitrobenzene. whereby (1.4 g of the objective compound in the form ofcrystals having a melting point of 275 2779C were obtained. Thiscompound was orange-colored. lts nitromethane solution showed a maximumabsorption wavelength (A max) of 548 nm and the extinction coefficient(5/10 of its molecule was 2.76.

As will be understood from the foregoing. the sensitizer's of thepresent invention can be obtained by effecting reaction between anacetyl coumarin derivative or acetyl naphthocoumarin derivative having adesired substituent and 2-hydroxybenzaldehyde or 2-hydroxynaphthoaldehyde having a desired substituent in the presence ofan acid having a desired anionic functional group.

The functional group corresponding to Z" in the foregoing generalformulas can be converted into another desired functional group byselecting the acid utilived in the above-described condensationring-closure reaction or by effecting reaction between the aforesaidproducts and acids having the desired functional groups or salts of suchacids.

Suitable examples of such acids or salts thereof include perchloricacid. periodic acid. phosphoricacid. hydrochloric acid. sulfuric acid.sodium borofluoride. sodium iodide. potassium iodide. sodium bromide.potassium iodide. dimethyl phosphate. and diphenyl phosphate.

Typical examples of compounds of formula (I) synthesized through theforegoing procedures are as fol lows:

2-[ 6-methoxy-3-( 1.2 )-benzopyronyl l-benzopyrylium perchlorate.6-methoxy-2-l 6-methoxy-3-( 1.2 benzopyronyll-benzopyrylium perchlorate.6- chloro-2-l 3-( 1.2 )-benzopyronyl l-benzopyrylium perchlorate. 2-16-chloro-3-( 1.2 )-benzopyronyl benzopyrylium perchlorate. 6-chloro-2-l6 methoxy-3-( 1.2 l-benzopyronyl l-benzopyrylium perchlorate.6-methoxy-2-[6-chloro-3-( l .2 )-benzopyronyll-benzopyryliumperchlorate. b-bromo- 2-[3-( 1.2)-benzopyronyll-benzopyryliumperchl'orate. 2-[ 6-bromo-3-( 1.2 )benzopyronyl l- 8 benzopyryliumperchlorate. 6-bromo-2-[6- methoxy- 3-( 1.2 -b'en7.opyronylI-benzopyrylium perchlorate. 1 6-methoxy-2-l6-bromo-3-l 1.2benxopyronyl-benzopyrylium perchlorate. 6-

bromo--Z-[ 6-ehloro-3-( 1.2 )-benzopyronyl benzopyrylium perchlorate.6-chloro-2-[fi-bromo- 3-( l .2 )-ben2opyronyl l-benzopyryliumperchlorate. 6-nitro-2-l 6-methoxy-3-( 1.2 )-ben7.opyronyl bcnzopyryliumperchlorate. 6.8-dibromo-2l6.8- dibromo-3-( l.2 )-b'enzopyronyll-benzopyrylium perchlorate. 6.8-'dibromo-2-l6-methoxy-3 (1.2)-benzopyronyll benzopyrylium perchlorate. 8-

me thoxy-2-[ 3-( 1.2 )-benzopyronyl l-benzopyrylium perchlorate.8-methoxy-2-l 6-methoxy'-3-( 1.2 benzopyronyll-benzopyrylium perchlorateand 8- methoxy-2-l 8-methoxy-3-( 1.2-benzopyronyl benzopyryliumperchlorate. Typical examples of the compounds of general formula (11)are as follows: i

2-[ 3- {1.2.B.a-( 7-nitronaphthophronyl benzopyrylium perchlorate.2-[3'-( l.2.,8.a( 1.2.3.04- naphthopyronyl)-6-methylbenzopyryliumperchlorate. 2-[3-{1.2.B.a-(7-chloronaphthopyronyl)}l-6-methylbenzopyrylium perchlorate. 2-[3-( l .2.,8.anaphthopyronyl]-6-chlorobenzopyrylium perchlorate. 2-[3-( 1.23.01-(8-methoxynaphthopyronyl ]-6.8-

dinitrobenzopyrylium perchlorate. 2-[3 {1,2,B.0z-(7-methylnaphthopyronyl ]-6- bromobenzopyrylium perchloratel.2.,8.a-naphthopyronyl ]-8- methoxybeniopyrylium perchlorate.

Typical examples of the compounds of general formula (111) are asfollows:

2[3( 1 ,2)-benzopyronyl]-7-nitro-fl naphthopyrylium perchlorate.2-[6-methoxy-3-(l ,2)-benzopyr0nyl]- 7-nitro-B-naphthopyryliumperchlorate. 2-[3- 1 .2)-benzopyronyl]-7-chloro-,B-naphth0pyryliumperchlorate. 2-[6-chloro-3-( l.2)-benzopyronyl]-7-chloro-B-naphthopyrylium perchlorate. 2-[6- methoxy-3 1.2)-benzopyronyl-9 -5.7-dinitro-B- naphthopyrylium perchlorate. 2-[6-chloro-3-( 1.2)- benzopyronyl l-5 .7-dinitro-B-naphthopyryliumperchlorate. 2-[ 6-methyl- 3-( 1.2 )-benzopyronyl]-5.7-

dinitro-fi naphthopyrylium perchlorate. 2-[3- l .2 l-ben'z'opyronyll-7-methoxy-B- naphthopyrylium perchlorate. 2-[3-( 1.2

benzopyronyl ];7-methyl-B-naphthopyrylium perchlorate and2-[6.8-dimethoxy-3-(1,2)- benzopyronyl l-fi-naphthopyrylium perchlorate.I And. typical examples of the compounds of general formula (IV) are asfollows:

2-[ 3-.( 1.2.B,a-naphthopyronyl ]-naphthopyrylium perchlorate. 2-[-iL2fiJ nitronaphthopyronyl)}] -B-naphthopyrylium perchlorate. 2-13-(''l.2$3.01-naphthopyronyl)]-7-nitro- B-naphthopyryliurn perchlorate. 2-13-{1 .2.B,a-(7- r itronaphthopyronyl); l-7-nitro-B naphthopyrylium'perchlorate. 2-[ 3-{1 .2.B.a-(7- ch loronaplithopyronyll} l -fi-naphthopyrylium perchlorate. n C 2 3'-( 1'.2.,8.a-naphthopyronyl)]-7-chlorofgnaphthopyryliurn perchlorate. 2-[3- I{1.2.3.6247-chloronaphthopyronyl)}l-7-chloro-B- naphthopyryliumperchlorate. 2-l3-{1.2.B.a-(8- methoxy naphthopyronyl)}]-7-methyl-B-naphthopyrylium perchlorate. 2-[3-{l.2.B,a-(8- methoxy naphthopyronyll-B-naphthopyrylium 9 perchlorate and 2-[3-t l.2.3.01-mtphthopyronyl)l-5.7-dinitro-B-naphthopyrylium perchlorate. The sensitizers according tothe present invention have superior efficiency in chemical and opticalsensitization of varieties of the known organic photoconductors andespecially displays the advantageous effect of imparting reproducibilityto the red-tinted original images in electrophotography. Typical of theorganic photoconductors which may be sensitized by mixing or dissolvingthe sensitizers of this invention therein are:

poly-N-vinyl carbazole. bromo-poly-N-vinyl carbazole.chloro-poly-N-vinyl carbazole. poly-3-vinyl- N-ethyl carbazole.poly-N-(N-acrylamide methyl) carbamoyl methyl carbazole, poly-N-(Nacrylamide methyl) carbamoyl ethyl carbazole, polyphenyl pyrazolc,poly-l-allyl-4,5-diphenyl imidazole, polyvinyl pyrene, polyvinylphenanthrene, polyacenaphthylene. polyvinyl dibenzothiophene. polyl-vinyl acridine, poly-N-allyl phenothiazine.poly-pdmidazoline-(Z)-styrene, polyvinyl anthracene.polyp-phenylene-l.3,4-oxidiazole, copolymer of anthracene-formalincondensation resin, copolymer of vinyl anthracene and N-vinyl carbazole,copolymer of 1,2-dihydroacenaphthene and indene, pyrene formaldehydecondensate, etc. The amount of sensitixer utilized with the foregoingorganic photoconductors is from 0.2 1.071 by weight. It is desirable toadd it to a solution of organic photo conductor upon dissolving it inthe least possible quan tity of a solvent such as nitromethane.

BRIEF DESCRIPTION OFTHE DRAWINGS In the appended drawings, FIGS. 1 19show the curves indicating respectively the spectral sensitivity of thesensitive paper provided with a sensitive film consisting of an organicphotoconductor sensitized with a sensitizer of the present invention.

The following are typical examples of the invention:

DESCRIPTION OF THE PREFERRED EMBODIMENTS Example 1 Each of thesensitizers No. I through No. 5 was dissolved in the minimum quantity ofnitromethane and each solution of sensitizer thus obtained was added to350g ofa chlorobenzene solution containing 6.7 weight 71 ofbromo-poly-N-vinyl carbazole in such a manner that the content of thesensitizer was 1.5 X mol per gr of bromo-poly-N-vinyl carbazole. Eachsolution pre pared as above was applied onto a stencil paper support bymeans ofa coating machine so as to form a film having a dry thickness of5p. and dried whereby five differ cnt electrophotographic sensitivepapers were prepared. By carrying the actual image-forming test on eachsensitive paper and examining the spectrogram and the surface potentialdecrement thereof, the sensitization effect was evaluated. First, afterimparting a negative electricity to each sensitive paper by means of acorona discharge of about 6 KV, the intensity of illumination on thesurface of the sensitive film was set at about 350 luxes with a whitelight as the light source, a projection exposure of an original imagewas conducted by the reflective projection'method for 0.2 0.5 second,and the thus exposed image was developed by the use of a liquiddeveloper for electrophotograph y prepared by dispersing a toner chargedwith a positiv'e electricity in isoparaffinic hydrocarbon and driedthereafter. whereby there was obtained an image faithful to the originalimage.

Next. by imparting a negative electricity to each of the same sensitivepapers as above also by means of a corona discharge of about 6 KV.exposing the thus electrified sensitive paper for 10 seconds to lightthrough a Zmm-wide slit by the use of a spectrograph. developing theresulting image with a liquid developer and thereafter drying by gentlyheating, a spectrogram was obtained respectively. The curves in FIGS. 15 of the appended drawings show the boundry between the portion havingthe toner of the developer attached thereto and the portion not havingsaid toner attached thereto in each spectrogram. and the number assignedto the drawing corresponds to the number assigned to the sensitizerapplied.

Further, upon electrifying each of the same sensitive papers as abovealso by means of a corona discharge of about 6 KV and applying whitelight of 30 luxes thereafter. the surface potential decrement wasexamined to find out the value of the photosensitivity of each sensitive paper in terms of E A; and E l/5 (lux. see).

In the following Table l. E /2 and E 1/5 express the applied lightvolume required for decreasing the surface potential to one halfand onefifth respectively. the photographic maximum wave-length expresses theob served value obtained by reading exactly the curves an the reflectedspectrum of FIGS. 1 5, the colorsensitivity expresses the percentage ofthe ratio of the reproduced concentration of the red-colored originalimage to the concentration of image at the time of rendering of theblack-colored original image with each ltis observed from FIGS. 1 5 thatthe sensitizers of the present invention have an excellent effect ofsensitizing an organic photoconductor to the extent of from about 400nmto about 700nm, and the showings in the foregoing table verify that thephotosensitivity of the thus sensitized organic photoconductor is verysatisfactory.

Example 2 A variety of electrophotographic sensitive papers wereprepared by combining various organic photoconductors with thesensitizers under the present invention and by applying the sameprocedure as that for Example 1. When the photosensitivity (E /z) ofthese sensi tive papers were examined, the results were as shown in thefollowing Table 2.

Table 2 lltulusensitivity ll. L 2) Quantity .sr'

sensiti/erapplied Organic photoconductor (UPC) Sensitiver Example 3 Byapplying the same procedure as that for Example 1 except for employingthe sensitizers No. 6 through No. 9 obtained in the foregoing syntheses(a) through (d) of the compounds of general formula (II), four differentelectrophotographic sensitive papers were prepared.

By carrying the actual image printing test on each sensitive paper bythe same method of test as in Example l and examining the spectrogramand the surface potential decrement thereof. the sensitization effectwas evaluated. The result of the evaluation was almost the same as thatin Example l. in this connection. the curves in FIGS. 6 9 of theappended drawings show the boundary between the portion having the tonerof the developer attached thereto and the portion not having said tonerattached thereto in each spectrogram. and the number assigned to thedrawing corresponds to the number assigned to the sensitizer applied.

Further, the photosensitivity in terms of E /2 and E 1/5 (lux sec) ofeach sensitive paper prepared in the present example was measured in thesame way as in Example 1. The results were as shown in the followingTable 3.

It is observed from FIGS. 6 9 that the sensitizers of this inventionhave an excellent effect of sensitizing an organic photoconductor to theextent of from about 4()()nm to about 7()()nm. and the showings in theforegoing Table 3 verify that the photosensitivity of the thussensitized organic photoconductor is very satisfactory.

Example 4 By combining those sensitizers employed for Example 3 withvarious organic photoconductors and applying the same procedure as thatfor Example 2, three different eleetrophotographic sensitive papers wereprepared. When the photosensitivity (E /2) of each sensi-' live paperwas measured. the results were as shown in the following Table 4.

By applying the same procedure as that for Example 1 except foremploying the sensitizers No. 10 through No. 14 obtained in theforegoing syntheses (a) through (c) of the compounds of the generalformula (III). five different eleetrophotographic sensitive papers wereprepared.

By carrying the actual image printing test on each sensitive paper bythe same method of test as in Example l and examining the spectrogramand the surface potential decrement thereof. the sensitization effectwas evaluated. The result of the evaluation was almost the same asthatin Example 1. in this connection. the curves in FIGS. 10 14 of theappended drawings show the boundary between the portion having the tonerof the developer attached thereto and the portion not having said tonerattached thereto in each spectrogram. and the number assigned to thedrawing corresponds to the number assigned to the sensitizer applied.

Further. the photosensitivity in terms of /2 and E 1/5 (lux-see) of eachsensitive paper prepared in the present example was measured in the sameway as in Example 1. The result was as shown in the following 'ltisobserved from FIGS. 10 14 that the sensitizers of this invention have anexcellent effect of sensitizing an organic photoconductor to the extentof from about 400nm to about 700mm, and the showings of the foregoingTable 5 verify that the photosensitivity of the thus sensitized organicphotoconductor is very satisfactory.

Example 6 By combining those sensitizers employed for Example5-with'various'organic photoconductors and applying the same procedureas that for Example 2, four differe'nt 'e'lectrophotographic sensitivepapers were prepared.-When the photosensitivity (E /2) of each sensi-'tive paper was measured. the results were as shown in :the followingTable 6.

By applying the same procedure as that for Example 1 except foremploying the sensitizers No. through No. 19 obtained in the foregoingsyntheses (a) through (c) of the compounds to be expressed by thegeneral formula (IV), five different electrophotographic sensitivepapers were prepared.

By carrying the image printing test on each sensitive paper by the samemethod of test as in Example 1 and examining the spectrogram and thesurface potential decrement thereof, the sensitization effect wasevaluated. The result of the evaluation was almost the same as that inExample I. In this connection, the curves in FlGS."l5 19 of the appendeddrawings show the boundary between the portion having the toner of thedeveloper attached thereto and the portion not having said tonerattached thereto in each spectrogram, and the number assigned to thedrawing corresponds to the number assigned to the sensitizer applied.

Further. the photosensitivity in terms of E /2 and E 1/5 (lux-sec) wasmeasured in the same way as in Example l. The results were as shown inthe following Table 7. 5

It is observed from FIGS. l5 19 that the sensitizers of this inventionhave an excellent effect of sensitizing an organic photoconductor to theextent of from about 400mm to about 700nm. and the showings of theforegoing Table 7 verify that the photosensitivity of the thussensitized photoconductor is very satisfactory.

Example 8 By combining these sensitizers employed for Example 7 withvarious organic photoconductors and applying the same procedure as thatfor Example 2, four kinds of electrophotographic sensitive papers wereperpared. When the photosensitivity (E /2) of each sensitive paper wasmeasured. the result was as shown in the following Table 8.

Table 8 Organic Quantity of Photopltotoconductor Sensitizer sensitizersensi- (OPC) applied tivity poly-N-vinyl LSXIO' carbazolc No. 15mol/gr.OPC 18.5 chloro-poly-N- vinyl carbazole No. 16 26.7 poly-N-(N-acrylamide No. [7 32.5 methyl) carhamoyl methyl carbazole poly-N-(N-acrylamide No. I) 38.4

methyl) carhamoyl ethyl carbazole What is claimed is:

1. A sensitized photoconductive composition comprising a polymericorganic photoconductor together with from 0.2 to 1.0% by weight based onthe weight of the photoconductor of a sensitizer having the formula:

wherein each of R and R represents a radical selected from the groupconsisting of hydrogen, alkyl having I 2 carbon atoms, alkoxy having 1 2carbon atoms, halogen and nitro, each of )1 and 11 represents an integerfrom 1 to 2 in the case where said R and. R represent a radical otherthan hydrogen, each of X and Y, when present represent a fused phenylnucleus having at most two substituents selected from the group definedfor said R and R and Z represents anionic functional group.

2. A sensitized photoconductive composition according to claim 1comprising a polymeric organic photoconductor together with from 0.2 to1.0% by weight based on the weight of the photoconductor of a sensitizerselected from the group consisting of 2-[6- methoxy-3-( l,2)-benzopyronyl]-benzopyrylium per chlorate, 6methoxy-2-[ 6-methoxy-3-( l.2 )-benzopyronyH-benzopyrylium perchlorate, 6-chloro-2-[3-(l,2)-benzopyronyl]-benzopyrylium perchlorate. 2-[6- chloro-3-( l ,2)-benzopyronyll-benzopyrylium perchlorate, 6-chloro-2-[6-methoxy-3-(l,2)-benzopyronyl]- benzopyrylium perchlorate. 6-methoxy-2-[6-ehloro-3-(l,2)-benzopyronyll-benzopyrylium perchlorate, 6-bromo-2-[3-(l,2)-benzopyronyl1-benzopyrylium perchlorate, 2-[6-bromo-3-( l,2)-benzopyronyl]- benzopyrylium perchlorate,6-bromo-2-[6-methoxy-3- (l,2)-benzopyronyll-benzopyrylium perchlorate,6- methoxy-2-[6-bromo-3-( l ,2)-benzopyronyl]- benzopyryliumperchlorate, 6-bromo-2-[6-chloro-3- (l,2)-benzopyronyl]-benzopyryliumperchlorate, 6-

chloro -2-[6-b romo-3-( 1,2)-benzopyronyl] -benzopyrylium perchlorate,6-nitro-2-[6-methoxy-3-(1l ,2 benzopyronyl]-benzopyrylium perchlorate,6,8- dibromo-2-[6,8-dibromo-3-( l ,2 )-benzopyronyl]- benzopyryliumperchlorate, 6,8-dibromo-2-[6- metho'xy-3-(l,2)-benzopyronyl1-benzopyrylium perchlorate, 8-methoxy-2-[3-( l ,2)-benzopyronyl]- benzopyrylium perchlorate, 8-methoxy-2-[6-methoxy-3-(l,2)-benzopyronyl]-benzopyrylium perchlorate, 8-methoxy-2-[8-methoxy-3-( 1,2)-benzopyronyl]- benzopyrylium perchlorate,2-[3- {1,2,B, a-(7- nitronaphthopyronyl) l-benzopyrylium perchlorate,2-[3-( 1,2,3, a-naphthopyronyl 6- methylbenzopyrylium perchlorate,2-[3-{l,2,B,a-(7- chloronaphthopyranyl)} ]-6-methylbenzopyryliumperchlorate, 2- 3-( l ,2,B,a-naphthopyronyl)]-6- chlorobenzopyryliumperchlorate, 2-[3-{1 ,2,,B,a- (8- methoxy-naphthopyronyl)}]-6.8-dinitrobenzopyrylium perchlorate, 2-[3-{l,2,B,a-(7-methylnaphthopyronyl) }]-6-bromobenzopyrylium perchlorate, 2-[3-(l,2,[3, a-naphtho pyronyl)]-8- methoxybenzopyrylium perchlorate, 2-[3-(l,2)- benzopyronyl] 7-nitrorB-naphthopyrylium perchlorate.2-[6-methoxy-3-( l,2)-benzopyronyl]-7-nitro-B- naphthopyryliumperchlorate, 2-[3-( 1 ,2(- benzopyronyl]-7-chloro-B-naphthopyryliumperchlorate, 2-[6-chloro-3-( l ,2)-benzopyronyl]7-chloro-B-naphthopyrylium perchlorate, 2-[6-methoxy-'3'-(l,2)-benzopyronyl1-5,7-dinitro-B-naphthopyrylium pcrchlorate, 2-[6-chl0ro-3-(l ,2)-benzopyronyl]-5,7- dinitro-B-naphthopyrylium perchlorate,2-[3-(l,2)- benzopyronyl]-7-methoxy-B-naphthopyrylium perchlorate, 2-[3-( l ,2 )-benzopyronyl]-7-methyl-B- naphthopyrylium perchlorate,2-[6,8-dimethoxy-3- l ,2)-benzopyronyl]-B-naphthopyrylium perchlorate,2-[3-( l ,2,B,a-naphthopyronyl)l-fi-naphthopyrylium perchlorate,2-[3-{1,2,B,a-(7-nitronaphthopyronyl)}]- B-naphthopyrylium perchlorate,2-[3-(1,2,B,oznaphthopyronyl)]-7-nitro -B-naphthopyrylium perchlorate,2-[3-{1,2,B,a-(7-nitronaphthopyronyl)}]-7- nitro-B-naphthopyryliumperchlorate, 2-[3-{l,2,l3,a- (7-chloronaphthopyrony1)J-B-naphthopyrylium perchlorate, 2-[3-( l.2,B,a-naphthopyronyl)]-7-chloro-B- naphthopyrylium perchlorate, 2-[3-{l ,2,B,a-(7- chloron'aphthopyronyU} ]-7-chloro-B-naphthopyryliumperchlorate, 2-[3-{1 ,2,B,0z-(8-methoxy naphthopyronyl)}]-7-methyl-,B-naphthopyrylium perchlorate, 2-[3- {l,2,,B,a-(8-methoxynaphthopyronyl)}J-B- naphthopyrylium perchlorate and 2-[3-(l,'2,B,anaphthopyronyl)]-5,7-dinitro-B-naphthopyrylium perchlorate.

3.'A sensitized photoconductive composition according to claim 1comprising a polymeric organic photoconductor together with from 0.2 to1.0% by weight,

based on the weight of the photoconductor of a sensitizer having thegeneral formula:

'16 wherein each of R and R represents hydrogen, an alkyl group having 1or 2 carbon atoms, an alkoxy group having 1 or 2 carbon atoms, halogenor nitro group; each of H and 11 represents an integer from 1 to 2 inthe case where said R and R represent a radical other than hydrogen.

4. A composition as in claim 1 wherein the sensitizer is2-[3-(l,2)-benzopyronyl]-benzopyryliurn perchlorate.

5. A composition as in claim 1 wherein the sensitizer is6-methoxy-2-[6methoxy-3-( l ,2)-benzopyronyl]- benzopyryliumperchlorate.

6. A composition as in claim 1 wherein the sensitizer is6-chloro-2-[6-chloro-3-( 1 ,2 )-benzopyronyl]- benzopyryliumperchlorate.

7. A composition as in claim 1 wherein the sensitizer is6-nitro-2-[6-nitro-3-( 1 ,2)-benzopyronyl]- benzopyrylium perchlorate.

8. A composition as in claim 1 wherein the sensitizer is6-bromo-2-[6-bromo-3-( l ,2)-benzopyronyl]- benzopyrylium perchlorate.

9. A sensitized photoconductive composition according to claim 1comprising a polymeric organic photoconductortogether with from 0.2 to1.0% by weight based on the weight of the photoconductor of a sensitizerhaving the general formula: V

wherein R R Z, n and n are respectively the same defined in the generalformula (I).

10. A composition as in claim 9 wherein the sensitizer is 2-[3-1,2,,8,a-naphthopyronyl)]-benzopyrylium perchlorate. I

11. A composition as in claim 9 wherein the sensitizer is {2-[3-l,2,,8,a-(7-nitronaphthopyronyl)}1-6- methoxybenzopyrylium perchlorate.

12. A composition as in claim 9 wherein the sensitizer is2-[3-{l,2,B,a-(7-chloro-naphthopyronyl)}1-6- chlorobenzopyryliumperchlorate.

13. A composition as in claim 9 wherein the sensitizer is 2-[ 3-( l.2,B,a-naphthopyronyl)]-6- methoxybenzopyrylium perchlorate.

14. A composition as in claim 9 wherein the sensitizer is 2-[3-{1,2,B,a(7-chlornaphthopyronyl)}]-6- methylbenzopyrylium perchlorate.

1 15. A sensitized photoconductive composition according to claim 1comprising a polymeric organic photoconductor together with from 0.2 to1.0% by weight based on the weight of the photoconductor of a sensitizerhaving the general formula wherein R,, R Z. I1 and 11 are respectivelythe same as defined in the general formula (I).

16. A composition as in claim 15 wherein the sensitizer is 2-[3-(l.2)-benzopyronyll-finaphthopyrylium perchlorate.

17. A composition as in claim 15 wherein the sensitizer is2-[6anethoxy-3-l l.3)-ben2op \'ronylI-finaphthopyrylium perchlorate.

18. A composition as in claim 15 wherein the sensitizer is2-[6-chloro-3-( l.2)-henzopyronyl1-13- naphthopyrylium perchlorate.

19. A composition as in claim 15 wherein the sensitizer is 2-[3-(1.2)-benzopyronyl]5.7-dinitro-finaphthopyrylium perchlorate.

20. A composition as in claim 15 wherein the sensitizer is2-[6-bromo-3-( l.2)-henzopyronyl]-B- naphthopyrylium perchlorate.

21. A sensitized photoconducting composition according to claim 1comprising a polymeric organic photoconductor together with from 0.2 to1.0% by weight based on theweight of the photoconductor of a sensitizerhaving the general formula:

wherein R R Z. n, and n: are respectively the same as defined inthegeneral formula (I).

22. A composition as in claim 21 wherein the sensitizer is 2-[ 3-( l.2,B,a-naphthopyronyl l-B- naphthopyrylium perchlorate.

23. A composition as in claim 21 wherein the sensitizer is2-[3-{1,2,B,a-(7-nitronaphthopyronyl)}]-7- nitro-B-naphthopyryliumperchlorate.

24. A composition as in claim 21 wherein the sensitizer is 2-[ 3- {l.2.,B,a-nitronaphthopyronyl) }]-B- naphthopyrylium perchlorate.

25. A composition as in claim 21 wherein the sensitizer is 2-[ 3- {l,2.B.a-9chloronaphthopyronyl l-B- naphthopyrylium perchlorate.

26. A composition as in claim 21 wherein the sensitizer is2-[3-(l,2,B,a-naphthopyronyl)l-9-chloro-B- naphthopyrylium perchlorate.

l l l=

1. A SENSITIZED PHOTOCONDUCTIVE COMPOSITION COMPRISING A POLYMERICORGANIC PHOTOCONDUCTOR TOGETHER WITH FROM 0.2 TO 1.0% BY WEIGHT BASED ONTHE WEIGHT OF THE PHOTOCONDUCTOR OF A SENSITIZER HAVING THE FORMULA: 2.A sensitized photoconductive composition according to claim 1 comprisinga polymeric organic photoconductor together with from 0.2 to 1.0% byweight based on the weight of the photoconductor of a sensitizerselected from the group consisting of2-(6-methoxy-3-(1,2)-benzopyronyl)-benzopyrylium perchlorate,6-methoxy-2-(6-methoxy-3-(1,2)-benzopyronyl)-benzopyrylium perchlorate,6-chloro-2-(3-(1,2)-benzopyronyl)-benzopyrylium perchlorate,2-(6-chloro-3-(1,2)-benzopyronyl)-benzopyrylium perchlorate,6-chloro-2-(6-methoxy-3-(1,2)-benzopyronyl)-benzopyrylium perchlorate,6-methoxy-2-(6-chloro-3-(1,2)-benzopyronyl)-benzopyrylium perchlorate,6-bromo-2-(3-(1,2)-benzopyronyl)-benzopyrylium perchlorate,2-(6-bromo-3-(1,2)-benzopyronyl)-benzopyrylium perchlorate,6-bromo-2-(6-methoxy-3-(1,2)-benzopyronyl)-benzopyrylium perchlorate,6-methoxy-2-(6-bromo-3-(1,2)-benzopyronyl)-benzopyrylium perchlorate,6-bromo-2-(6-chloro-3-(1,2)-benzopyronyl)-benzopyrylium perchlorate,6-chloro-2-(6-bromo-3-(1,2)-benzopyronyl) -benzopyrylium perchlorate,6-nitro-2-(6-methoxy-3-(1,2)-benzopyronyl)-benzopyrylium perchlorate,6,8-dibromo-2-(6,8-dibromo-3-(1,2)-benzopyronyl)-benzopyryliumperchlorate,6,8-dibromo-2-(6-methoxy-3-(1,2)-benzopyronyl)-benzopyryliumperchlorate, 8-methoxy-2-(3-(1,2)-benzopyronyl)-benzopyryliumperchlorate, 8-methoxy-2-(6-methoxy-3-(1,2)-benzopyronyl)-benzopyryliumperchlorate, 8-methoxy-2-(8-methoxy-3-(1,2)-benzopyronyl)-benzopyryliumperchlorate, 2-(3-(1,2, Beta , Alpha-(7-nitronaphthopyronyl)))-benzopyrylium perchlorate, 2-(3-(1,2, Beta ,Alpha -naphthopyronyl))-6-methylbenzopyrylium perchlorate, 2-(3-(1,2,Beta , Alpha -(7-chloronaphthopyranyl)))-6-methylbenzopyryliumperchlorate, 2-(3-(1,2, Beta , Alpha-naphthopyronyl))-6-chlorobenzopyrylium perchlorate, 2-(3-(1,2, Beta ,Alpha -(8-methoxy-naphthopyronyl)))-6,8-dinitrobenzopyryliumperchlorate, 2-(3-(1,2, Beta , Alpha-(7-methylnaphthopyronyl)))-6-bromobenzopyrylium perchlorate, 2-(3-(1,2,Beta , Alpha -naphthopyronyl))-8-methoxybenzopyrylium perchlorate,2-(3-(1,2)-benzopyronyl)-7-nitro- Beta -naphthopyrylium perchlorate,2-(6-methoxy-3-(1,2)-benzopyronyl)-7-nitro- Beta -naphthopyryliumperchlorate, 2-(3-(1,2(-benzopyronyl)-7-chloro- Beta -naphthopyryliumperchlorate, 2-(6-chloro-3-(1,2)-benzopyronyl)-7-chloro- Beta-naphthopyrylium perchlorate,2-(6-methoxy-3-(1,2)-benzopyronyl)-5,7-dinitro- Beta -naphthopyryliumperchlorate, 2-(6-chloro-3-(1,2)-benzopyronyl)-5,7-dinitro- Beta-naphthopyrylium perchlorate, 2-(3-(1,2)-benzopyronyl)-7-methoxy- Beta-naphthopyrylium perchlorate, 2-(3-(1,2)-benzopyronyl)-7-methyl- Beta-naphthopyrylium perchlorate, 2-(6,8-dimethoxy-3-(1,2)-benzopyronyl)-Beta -naphthopyrylium perchlorate, 2-(3-(1,2, Beta , Alpha-naphthopyronyl))- Beta -naphthopyrylium perchlorate, 2-(3-(1,2, Beta ,Alpha -(7-nitronaphthopyronyl)))- Beta -naphthopyrylium perchlorate,2-(3-(1,2, Beta , Alpha -naphthopyronyl))-7-nitro - Beta-naphthopyrylium perchlorate, 2-(3-(1,2, Beta , Alpha-(7-nitronaphthopyronyl)))-7-nitro- Beta -naphthopyrylium perchlorate,2-(3-(1,2, Beta , Alpha -(7-chloronaphthopyronyl)) )- Beta-naphthopyrylium perchlorate, 2-(3-(1,2, Beta , Alpha-naphthopyronyl))-7-chloro- Beta -naphthopyrylium perchlorate,2-(3-(1,2, Beta , Alpha -(7-chloronaphthopyronyl)))-7-chloro- Beta-naphthopyrylium perchlorate, 2-(3-(1,2, Beta , Alpha -(8-methoxynaphthopyronyl)))-7-methyl- Beta -naphthopyrylium perchlorate,2-(3-(1,2, Beta , Alpha -(8-methoxy naphthopyronyl)))- Beta-naphthopyrylium perchlorate and 2-(3-(1,2, Beta , Alpha-naphthopyronyl))-5,7-dinitro- Beta -naphthopyrylium perchlorate.
 3. Asensitized photoconductive composition according to claim 1 comprising apolymeric organic photoconductor together with from 0.2 to 1.0% byweight based on the weight of the photoconductor of a sensitizer havingthe general formula:
 4. A composition as in claim 1 wherein thesensitizer is 2-(3-(1,2)-benzopyronyl)-benzopyrylium perchlorate.
 5. Acomposition as in claim 1 wherein the sensitizer is6-methoxy-2-(6-methoxy-3-(1,2)-benzopyronyl)-benzopyrylium perchlorate.6. A composition as in claim 1 wherein the sensitizer is6-chloro-2-(6-chloro-3-(1,2)-benzopyronyl)-benzopyrylium perchlorate. 7.A composition as in claim 1 wherein the sensitizer is6-nitro-2-(6-nitro-3-(1,2)-benzopyronyl)-benzopyrylium perchlorate.
 8. Acomposition as in claim 1 wherein the sensitizer is6-bromo-2-(6-bromo-3-(1,2)-benzopyronyl)-benzopyrylium perchlorate.
 9. Asensitized photoconductive composition according to claim 1 comprising apolymeric organic photoconductor together with from 0.2 to 1.0% byweight based on the weight of the photoconductor of a sensitizer havingthe general formula:
 10. A composition as in claim 9 wherein thesensitizer is 2-(3-(1,2, Beta , Alpha -naphthopyronyl))-benzopyryliumperchlorate.
 11. A composition as in claim 9 wherein the sensitizer is2-(3-(1,2, Beta , Alpha-(7-nitronaphthopyronyl)()-6-methoxybenzopyrylium perchlorate.
 12. Acomposition as in claim 9 wherein the sensitizer is 2-(3-(1,2, Beta ,Alpha -(7-chloro-naphthopyronyl)))-6-chlorobenzopyrylium perchlorate.13. A composition as in claim 9 wherein the sensitizer is 2-(3-(1,2,Beta , Alpha -naphthopyronyl))-6-methoxybenzopyrylium perchlorate.
 14. Acomposition as in claim 9 wherein the sensitizer is 2-(3-(1,2, Beta ,Alpha -(7-chlornaphthopyronyl)))-6-methylbenzopyrylium perchlorate. 15.A sensitized photoconductive composition according to claim 1 comprisinga polymeric organic photoconductor together with from 0.2 to 1.0% byweight based on the weight of the photoconductor of a sensitizer havingthe general formula
 16. A composition as in claim 15 wherein thesensitizer is 2-(3-(1,2)-benzopyronyl)- Beta -naphthopyryliumperchlorate.
 17. A composition as in claim 15 wherein the sensitizer is2-(6-methoxy-3-(1,2)-benzopyronyl)- Beta -naphthopyrylium perchlorate.18. A composition as in claim 15 wherein the sensitizer is2-(6-chloro-3-(1,2)-benzopyronyl) - Beta -naphthopyrylium perchlorate.19. A composition as in claim 15 wherein the sensitizer is2-(3-(1,2)-benzopyronyl)-5,7-dinitro- Beta -naphthopyrylium perchlorate.20. A composition as in claim 15 wherein the sensitizer is2-(6-bromo-3-(1,2)-benzopyronyl)- Beta -naphthopyrylium perchlorate. 21.A sensitized photoconducting composition according to claim 1 comprisinga polymeric organic photoconductor together with from 0.2 to 1.0% byweight based on the weight of the photoconductor of a sensitizer havingthe general formula:
 22. A composition as in claim 21 wherein thesensitizer is 2-(3-(1,2, Beta , Alpha -naphthopyronyl))- Beta-naphthoPyrylium perchlorate.
 23. A composition as in claim 21 whereinthe sensitizer is 2-(3-(1,2, Beta , Alpha-(7-nitronaphthopyronyl)()-7-nitro- Beta -naphthopyrylium perchlorate.24. A composition as in claim 21 wherein the sensitizer is 2-(3-(1,2,Beta , Alpha -nitronaphthopyronyl)))- Beta -naphthopyrylium perchlorate.25. A composition as in claim 21 wherein the sensitizer is 2-(3-(1,2,Beta , Alpha -9-chloronaphthopyronyl)))- Beta -naphthopyryliumperchlorate.
 26. A composition as in claim 21 wherein the sensitizer is2-(3-(1,2, Beta , Alpha -naphthopyronyl))-9-chloro- Beta-naphthopyrylium perchlorate.